diff options
Diffstat (limited to 'lib/clzti2.c')
-rw-r--r-- | lib/clzti2.c | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/lib/clzti2.c b/lib/clzti2.c new file mode 100644 index 000000000000..805688fbe223 --- /dev/null +++ b/lib/clzti2.c @@ -0,0 +1,33 @@ +/* ===-- clzti2.c - Implement __clzti2 -------------------------------------=== + * + * The LLVM Compiler Infrastructure + * + * This file is distributed under the University of Illinois Open Source + * License. See LICENSE.TXT for details. + * + * ===----------------------------------------------------------------------=== + * + * This file implements __clzti2 for the compiler_rt library. + * + * ===----------------------------------------------------------------------=== + */ + +#if __x86_64 + +#include "int_lib.h" + +/* Returns: the number of leading 0-bits */ + +/* Precondition: a != 0 */ + +si_int +__clzti2(ti_int a) +{ + twords x; + x.all = a; + const di_int f = -(x.s.high == 0); + return __builtin_clzll((x.s.high & ~f) | (x.s.low & f)) + + ((si_int)f & ((si_int)(sizeof(di_int) * CHAR_BIT))); +} + +#endif /* __x86_64 */ |